Recently, a radial ply carcass has been used for motorcycle tires. Such a motorcycle radial tire has been made based on the technique for four-wheeled vehicle tires, e.g. passenger car tires. That is, the tire has been provided with a belt reinforcement formed as follows: a rubberized fabric (d) is cut bias at a small angle (alpha) to the cord direction as shown in FIG. 17, which is usually 15 to 30 degrees; and the cut fabric (e) is wound around a carcass with connecting the ends (f) as shown in FIG. 16 to form an annular belt reinforcement (a), and accordingly, the laid angle of the belt cords (b) to the tire equator becomes the same bias angle (alpha). In such a bias belt structure, however, steering stability during straight running and cornering, especially at high speed, is not good.
On the other hand, Japanese Utility-Model Publication No. 58-160805 discloses a belt making method, in which a belt cord is wound spirally and continuously from its one edge to the other edge at a generally zero angle to the circumferential direction of the tire so as to form a jointless belt. When this is used in the motorcycle tire, instead of the conventional belt, high speed steering stability can be improved, but belt edge separation failure and deterioration of tire uniformity are often observed.